Geranylated flavanones from the secretion on the surface of the immature fruits of Paulownia tomentosa

Chemical investigation of the methanol extract of the viscous secretion on the surface of immature fruits of Paulownia tomentosa furnished nine geranylated flavanones, 6-geranyl-5,7-dihydroxy-3',4'-dimethoxyflavanone (1), 6-geranyl-3',5,7-trihydroxy-4'-methoxyflavanone (2), 6-geranyl-4',5,7-trihydroxy-3',5'-dimethoxyflavanone (3), 6-geranyl-4',5,5',7-tetrahydroxy-3'-methoxyflavanone (4), 6-geranyl-3,3',5,7-tetrahydroxy-4'-methoxyflavanone (5), 4',5,5',7-tetrahydroxy-6-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]-3'-methoxyflavanone (6), 3,3',4',5,7-pentahydroxy-6-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]flavanone (7), 3,3',4',5,7-pentahydroxy-6-[7-hydroxy-3,7-dimethyl-2(E)-octenyl]flavanone (8), and 3,4',5,5',7-pentahydroxy-3'-methoxy-6-(3-methyl-2-butenyl)flavanone (9), along with six known geranylated flavanones. Among these, compounds 4, 6-9 and the known 6-geranyl-3',4',5,7-tetraahydroxyflavanone (diplacone), 6-geranyl-3,3',4',5,7-pentahydroxyflavanone (diplacol) and 3',4',5,7-pentahydroxy-6-[7-hydroxy-3,7-dimethyl-2(E)-octenyl]flavanone showed potent radical scavenging effects towards DPPH radicals.     

Coumarins and chromones from Lomatium macrocarpum

Roots of Lomatium macrocarpum (Hook. & Arn.) C. & R. yielded osthol (7-methoxy-8-[3-methyl-2-butenyl]-coumarin) and a chromone, 2-methyl-5-hydroxy-6-[3-methyl-2-butenyl]-7-methoxychromone, identified spectroscopically and by synthesis. The aerial parts of the plant also contained this chromone along with sibiricin (5,7-dimethoxy-8-[3-methyl-2,3-epoxybutyl]-coumarin) and a new coumarin named macrocarpin. By spectroscopy and chemical degradation macrocarpin was shown to be 7-methoxy-8-(3-methyl-4-[2-methyl-cis-2-butenoyloxy]-cis-2-butenyl)coumarin. These products were not found in four other Lomatium species examined.     

Geranylated phenolic constituents from the fruits of Artocarpus nobilis

Chemical investigation of the combined dichloromethane and ethyl acetate extracts of the fruits of Artocarpus nobilis, furnished four new geranylated phenolic constituents, 2,4,4'-trihydroxy-3-[(2E)-5-methoxy-3,7-dimethylocta-2,6-dienyl]chalcone (4), 1-(3,4-dihydro-3,5-dihydroxy-2-methyl-2-(3-methyl-2-butenyl)-2H-1-benzopyran-6-yl-3-(4-hydroxyphenyl)-2(E)-propen-1-one (5), 8-geranyl-3',4',7-trihydroxyflavone (8), 3'-geranyl-4',5,7-trihydroxyflavanone (9), together with known related compounds, xanthoangelol (1), xanthoangelol B (2), 3-geranyl-2,3',4,4'-tetrahydroxychalcone (3), lespeol (6), 8-geranyl-4',7-dihydroxyflavanone (7), and isonymphaeol-B (10). Compounds 3, 8 and 10 showed strong antioxidant activity against DPPH radical by spectrophotometric method.     

Homoisoflavonoids from Ophiopogon japonicus Ker-Gawler

From the ethyl acetate extract of the tuberous roots of Ophiopogon japonicus (Liliaceae) eight known and five new homoisoflavonoidal compounds were isolated. The new compounds are 5,7-dihydroxy-8-methoxy-6-methyl-3-(2'-hydroxy-4'-methoxybenzyl)chroman-4-one (1), 7-hydroxy-5,8-dimethoxy-6-methyl-3-(2'-hydroxy-4'-methoxybenzyl)chroman-4-one (2), 5,7-dihydroxy-6,8-dimethyl-3-(4'-hydroxy-3'-methoxybenzyl)chroman-4-one (3), 2,5,7-trihydroxy-6,8-dimethyl-3-(3',4'-methylenedioxybenzyl)chroman-4-one (4) and 2,5,7-trihydroxy-6,8-dimethyl-3-(4'-methoxybenzyl)chroman-4-one (5). Their structures have been elucidated by mass and NMR spectroscopy. Compounds 4 and 5 are the first isolated homoisoflavonoids with a hemiacetal function at position 2.     

Molecular docking based screening of neem-derived compounds with the NS1 protein of Influenza virus

AbbreviationsNS1 protein - Non Structural 1 proteinNA - Neuraminidase, HA - Hemagglutinin, M - Matrix, 127-40-2 - 4-[(1E, 3E, 5E,7Z, 9E, 11E, 13E, 15E, 17E)-18-(4-hydroxy-2,6,6-trimethylcyclohex-2-en-1-yl)-3,7,12,16-tetramethyloctadeca-1,3,5,7,9,11,13,15,17- nonaenyl]-3, 5, 5-trimethylcyclohex-3-en-1-ol, Quercitrin 2 - (3,4-dihydroxyphenyl)-5,7-dihydroxy-3- [(2S,3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxychromen-4-one, Tiplasinin 2 - [1-benzyl-5-[4-(trifluoromethoxy) phenyl] indol-3-yl]-2-oxoacetic acid, Hyperoside 2 - (3,4-dihydroxyphenyl)-5,7-dihydroxy-3- [(2S,3R,4S,5R,6R)-3, 4, 5-trihydroxy-6- (hydroxymethyl)oxan-2- yl]oxychromen-4-one LGH 4-(2-chloro-4-nitrophenyl)piperazin-1-yl][3-(2-methoxyphenyl)-5-methyl-1,2-oxazol-4-yl]methanone, nRUTIN 2 - (3, 4-dihydroxyphenyl) -5, 7-dihydroxy-3-[(2S, 3R, 4S, 5S, 6R)-3, 4, 5-trihydroxy-6-[[(2R, 3R, 4R, 5R, 6S)-3,4,5-trihydroxy- 6-methyloxan-2-yl]oxymethyl]oxan-2-yl]oxychromen-4-one.     

Three isoflavanones with cannabinoid-like moieties from Desmodium canum

Three further derivatives of 5,7,2',4'-tetrahydroxy-6-methyl isoflavanone have been isolated from the root extract of Desmodium canum and assigned the structures 2,3-dihydro-5,7-dihydroxy-6-methyl-3-(1a,2,3,3a,8b,8c-hexahydro-6-hydroxy-1,1,3a-trimethyl-1H-4-oxabenzo[f]cyclobut[c,d]inden-7-yl)-4H-1-benzopyran-4-one (1) 2,3-dihydro-5,7-dihydroxy-6-methyl-3-(6a,7,8,10a-tetrahydro-3-hydroxy-6,6,9-trimethyl-6H-dibenzo[b,d]pyran-2-yl)-4H-1-benzopyran-4-one (2) 2,3-dihydro-5,7-dihydroxy-6-methyl-3-(3-hydroxy-6,6,9-trimethyl-6H-dibenzo[b,d]pyran-2-yl) 4H-1-benzopyran-4-one (3). The three compounds and the previously isolated chromene 4 all derive from the geranylated precursor 5 by a series of cannabinoid-like oxidative rearrangements.     

Xanthones from Hypericum chinense

Six xanthones, 1,3,7-trihydroxy-2-(2-hydroxy-3-methyl-3-butenyl)-xanthone (1), 1,7-dihydroxy-2,3-[2'-(1-hydroxy-1-methylethyl)-dihydrofurano]-xanthone (2), 1,3,7-trihydroxy-5-methoxyxanthone (3), 1,7-dihydroxy-5,6-dimethoxyxanthone (4), 4,5-dihydroxy-2,3-dimethoxyxanthone (5), 1,3-dihydroxy-2,4-dimethoxyxanthone (6) and 21 known xanthones were isolated from the leaves and stems of Hypericum chinense. Their structures were established based on spectroscopic studies.     

Isolation of novel phenolic compounds with multidrug resistance (MDR) reversal properties from Onychium japonicum

We isolated seven novel compounds, namely, 3',4',6-trihydroxy-2,4-dimethoxy-3-(3″,4″-dihydroxybenzyl)chalcone (1), 3',6-dihydroxy-2,4,4'-trimethoxy-3-(3″,4″-dihydroxybenzyl)chalcone (2), α,β-dihydro-3',6-dihydroxy-2,4,6'-trimethoxy-3-(3″,4″-dihydroxybenzyl)chalcone (3), 3',4,4'-trihydroxy-2,6-dimethoxychalcone (4), 4',5,7-trihydroxy-6-(3″,4″-dihydroxybenzyl)flavone (5), 3-(3',4'-dihydroxybenzyl)-6,7-dihydroxycoumarin (6), 3-(3',4'-dihydroxyphenyl)-3,4-dihydroisocoumarin (7), as well as a known compound, 3',4',7-trihydroxy-5-methoxyflavanone (8) from the whole grass of Onychium japonicum, and elucidated their structures by spectroscopic methods. Compounds 1-3 exhibited significant multidrug resistance (MDR) reversal effects on MCF-7/ADR and Bel-7402/5-Fu cell lines.     

MK-8825: a potent and selective CGRP receptor antagonist with good oral activity in rats

Rational modification of the clinically tested CGRP receptor antagonist MK-3207 (3) afforded an analogue with increased unbound fraction in rat plasma and enhanced aqueous solubility, 2-[(8R)-8-(3,5-difluorophenyl)-8-methyl-10-oxo-6,9-diazaspiro[4.5]dec-9-yl]-N-[(6S)-2'-oxo-1',2',5,7-tetrahydrospiro[cyclopenta[b]pyridine-6,3'-pyrrolo[2,3-b]pyridin]-3-yl]acetamide (MK-8825) (6). Compound 6 maintained similar affinity to 3 at the human and rat CGRP receptors but possessed significantly improved in vivo potency in a rat pharmacodynamic model. The overall profile of 6 indicates it should find utility as a rat tool to investigate effects of CGRP receptor blockade in vivo.     

Formation of Glucose Isomerase by Streptomyces sp.

Sophoradin (I) [2′,4,4′-trihydroxy-3,3′,5-tris(3-methyl-2-butenyl)chalcone] which had been isolated from “Guang-Dou-Gen” (the root of Sophora subprostrata Chun et T. Chen) was synthesized through Claisen rearrangement. The reaction of p-hydroxybenzaldehyde and 3-chloro-3-methyl-1-butyne (III) gave 4-(1,1-dimethylpropargyloxy)benzaldehyde (VIII), which was catalytically hydrogenated over Lindlar catalyst to afford 4-(1,1-dimethylallyloxy)benzaldehyde (IX). IX was converted to 4-hydroxy-3-(3-methyl-2-butenyl)benzaldehyde (X) by Claisen rearrangement. The reaction of X and III gave 3-(3-methyl-2-butenyl)-4-(1,1-dimethylpropargyloxy)benzaldehyde (XI). Condensation of 2-hydroxy-4-(1,1-dimethylpropargyloxy)acetophenone (IV) and XI in alkaline solution gave a chalcone (XIII), which was catalytically hydrogenated over Lindlar catalyst to give 2′-hydroxy-4,4′-bis(1,-dimethylallyloxy)-3-(3-methyl-2-butenyl)chalcone (XIV). XIV was converted to I by Claisen rearrangement.     

Geranyl chalcone derivatives with antifungal and radical scavenging properties from the leaves of Artocarpus nobilis

Antifungal activity guided fractionation of the n-butanol extract from the methanol extract of the leaves of Artocarpus nobilis furnished 2',4',4-trihydroxy-3'-geranylchalcone (1), 2 ',4',4-trihydroxy-3'-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]chalcone (2), 2',4',4-trihydroxy-3'-[2-hydroxy-7-methyl-3-methylene-6-octaenyl]chalcone (3), 2',3,4,4'-tetrahydroxy-3'-geranylchalcone (4), 2',3,4,4'-tetrahydroxy-3'-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]chalcone (5). The chalcones 3 and 5 are new natural products whereas 1 and 2 are reported first time from the family Moraceae. All these compounds showed good fungicidal activity against Cladosporium cladosporioides and high radical scavenging activity towards the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical in TLC bio-autography method.     

Benzophenones of Garcinia pseudoguttifera (Clusiaceae)

Four biogenetically related benzophenones have been isolated from the Fijian Garcinia pseudoguttifera. They are: 6-hydroxy-2,4-dimethoxy-3,5-bis(3-methyl-2-butenyl)benzophenone (myrtiaphenone-A); 2,2-dimethyl-8-benzoyl-7-hydroxy-5-methoxy-6-(3-methyl-2-butenyl)benzopy ran (myrtiaphenone-B); 2,6-dihydroxy-4-methoxy-3,5-bis(3-methyl-2-butenyl)benzophenone (vismiaphenone-C) and a new benzophenone, 2,2-dimethyl-8-benzoyl-3,7-dihydroxy-5-methoxy- 6-(3-methyl-2-butenyl)-3,4-dihydrobenzopyran (pseudoguttiaphenone-A). Pseudoguttiaphenone-A could be biogenetically derived from vismiaphenone-C. The major component of G. pseudoguttifera was identified as eupha-8,24-dien-3 beta-ol.     

Antimicrobial acylphloroglucinols and dibenzyloxy flavonoids from flowers of Helichrysum gymnocomum

From the dichloromethane extract of the flowers of Helichrysum gymnocomum (Asteraceae) two known flavonoids, 4 and 5, and a known acylphloroglucinol, 3B, were isolated. In addition to 1 and 2, the 4′,6′-dibenzyloxy-2′-hydroxy derivative of 2′,4′,6′-trihydroxychalcone and 5,7-dibenzyloxy derivative of pinocembrin, respectively, are reported in Nature for the first time. A compound 3A, related to 3B has the structure 2-methyl-1-[2,4,6-trihydroxy-3-(2-hydroxy-3-methyl-3-butenyl)phenyl]-1-propanone. Compounds 1, 2, 3A, 3B, 4 and 5 have MIC values below 64 μg/ml against a selection of pathogens, with 3B having the highest sensitivity (6.3–45 μg/ml) for eight of the ten pathogens tested, including Staphylococcus aureus (6.3 μg/ml) and methicillin and gentamycin resistant strain of S. aureus (7.8 μg/ml). With the exception of 2, the other compounds had notable activity (45–63 μg/ml) towards Pseudomonas aeruginosa.     

Detailed biosynthetic pathway to decaprenoxanthin diglucoside in Corynebacterium glutamicum and identification of novel intermediates

Carotenogenic mutants of Corynebacterium glutamicum were analyzed for their carotenoid content. Mutant MV10 accumulated the same carotenoids as the wild-type, decaprenoxanthin, decaprenoxanthin monoglucoside, and (2R,6R,2'R,6'R)-decaprenoxanthin di-(beta-D)-glucoside, but in three-fold higher amounts. In addition, decaprenoxanthin diglucoside fatty acid esters and the intermediates nonaprene, 2-(3-methyl-2-butenyl)-epsilon,psi-carotene, and sarcinene, 2,2'-bis(3-methyl-2-butenyl)-epsilon,epsilon-carotene were identified as minor carotenoids. The pink mutants MV40 and MV60 synthesized only lycopene. From another pink mutant, MV70, novel C(50)-carotenoids were isolated. By NMR and mass spectroscopy, nonaflavuxanthin, 2-(4-hydroxy-3-methyl-2-butenyl)-1,16-didehydro-1,2-dihydro-psi,psi-carotene, and flavuxanthin, 2,2'-bis(4-hydroxy-3-methyl-2-butenyl)-1,16,1',16'-tetradehydro-1,2,1',2'-tetrahydro-psi,psi-carotene, were identified. The identification of these intermediates revealed the detailed pathway for the formation of decaprenoxanthin derivatives in Corynebacterium glutamicum.     

Homoisoflavanones from Disporopsis aspera

From cytotoxic extracts of the roots of Disporopsis aspera Engl. (Liliaceae) a homoisoflavanone, disporopsin (3-(2',4'-dihydroxy-benzyl)-5,7-dihydroxy-chroman-4-one) (1) and three rare methyl-homoisoflavanones, 3-(4'-hydroxy-benzyl)-5,7-dihydroxy-6-methyl-chroman-4-one (2), 3-(4'-hydroxy-benzyl)-5,7-dihydroxy-6,8-dimethyl-chroman-4-one (3) and 3-(4'-hydroxy-benzyl)-5,7-dihydroxy-6-methyl-8-methoxy-chroman-4- one (4) along with five other known compounds, N-trans-feruloyl tyramine (5), adenine (6), 5-(hydroxymethyl)-2-furfural (7), beta-sitosterol (8) and beta-sitosteryl glucopyranoside (9) were isolated. The structures of compounds 1-2 were elucidated by spectral data (1, 2-D NMR and EIMS). The four homoisoflavanones (1-4) were found to be cytotoxic against a series of human cancer cell lines (HCT15, T24S, MCF7, Bowes, A549 and K562) with IC(50) ranging from 15 to 200 microM. Possible biosynthesis routes for homoisoflavonoids (1-4) are discussed.     

Platachromone A–D: Cytotoxic 2-styrylchromones from the bark of Platanus × acerifolia (Aiton) Willd.

Four novel 2-styrylchromones, 4′,5,7-trihydroxy-6-isopentene-2-styrylchromone (1), 4′,5,7-trihydroxy-8-isopentene-2-styrylchromone (2), 4′,5,7-trihydroxy-6-(2-hydroxy-3-methylbut-3-enyl)-2-styrylchromone (3) and 4′,5,7-trihydroxy-8-(2-hydroxy-3-methylbut-3-enyl)-2-styrylchromone (4), were isolated from shed bark of Platanus × acerifolia (Aiton) Willd., as well as four known compounds, 4′,5,7-trihydroxy-2-styrylchromone (5), scutellarein (6), 4′,5,7-trihydroxy-6-prenylflavone (7), and 4′,5,7-trihydroxy-8-prenylflavone (8). The structures of compounds 1–4 were established by direct interpretation of their spectral data, mainly high resolution electrospray ionization mass spectrometry (HR-ESI-MS), 1D and 2D NMR (¹H–¹H COSY, HSQC and HMBC). The cytotoxicity of the compounds 1–8 was evaluated in four human carcinoma cell lines, including HepG2, SMMC-7721, MDA-MB-231, and KB. Compounds 1–4 exhibited significantly cytotoxic activity toward HepG2 and KB cells, with IC₅₀ values ranging from 3.0 to 9.7 μM.     

Anthraquinones from the fruits of Vismia laurentii

Phytochemical study of the fruits of Vismia laurentii resulted in the isolation of five structurally related compounds. Three of them are constituents, namely, laurentiquinone A (1) (methyl 1,6,8-trihydroxy-3-methyl-7-(3-methylbut-2-enyl)-9,10-dioxo-9,10-dihydroanthracene-2-carboxylate), laurentiquinone B (2) (methyl 5,7-dihydroxy-2,2,9-trimethyl-6,11-dioxo-6,11-dihydro-2H-anthra[2,3-b]pyran-8-carboxylate) and laurentiquinone C (3) (methyl 9-(ethanoyloxymethyl)-5,7-dihydroxy-2,2-dimethyl-6,11-dioxo-6,11-dihydro-2H-anthra[2,3-b]pyran-8-carboxylate) and two are known compounds, emodin (4) and isoxanthorin (5). Their structures were elucidated by spectroscopic means. Crude extracts of hexane and EtOAc showed anti-plasmodial activity against the W2 strain of Plasmodium falciparum.     

Two flavanones from the root bark of Lespedeza Davidii

Two new flavanones have been isolated from the root bark of Lespedeza davidii and their structures established as 6,8-di-γ,γ-dimethylallyl-4′-methyoxy-5,7,2′-trihydroxy-(2S)-flavanone and 8,3′-di-γ,γ-dimethylallyl-5,7,4′-trihydroxy-(2S)-flavanone on the basis of spectroscopic evidence.     

Phenolic derivatives from Wigandia urens with weak activity against the chemokine receptor CCR5

Three compounds, 2,3-dihydroxy-4-methoxy-6,6,9-trimethyl-6H-dibenzo[b,d]pyran (1), 8-methoxy-2-methyl-2-(4-methyl-3-pentenyl)-2H-1-benzopyran-6-ol (2) and 4-methoxy-3-(3-methyl-2-butenyl)-benzoic acid (3), have been isolated from Wigandia urens. The structures of compounds 1, 2 and 3 were determined from spectroscopic data and showed activity in a CCR5 assay with IC(50) values of 33, 46 and 26 muM respectively.     

樱草杜鹃中的黄酮类化合物

从樱草杜鹃（Rhododendron primulaeflorum）地上部分的乙醇提取物中分离得到10个黄酮类化合物,经理化性质及波谱分析,鉴定为杜鹃素（1）、4’,5,7-三羟基-8-甲基黄烷酮（2）、二氢山柰酚（3）、异鼠李素（4）、槲皮素（5）、陆地棉苷（6）、瑞诺苷（7）、（2R,3R）－花旗松素-3—O-α-L-吡喃阿拉伯糖苷（8）、（2R,3S）-花旗松素-3—O-α-L-吡喃阿拉伯糖苷（9）、（2S,3R）－花旗松素－3－O－α－L－吡喃阿拉伯糖苷（10）。所有化合物均为首次从该植物中分得。